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    <title>数组求和及平均值</title>
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<body>
    <script>
        //1. 求数组[2, 6, 1, 7, 4] 里面所有元素的和以及平均值

        let arr = [2,6,1,7,4];
        let sum = 0;
        for (let i = 0; i < arr.lentgh; i++){
            sum = sum + arr[i];
        }
        console.log('数组的和'+sum);
        console.log('数组的平均数是' +sum / arr.length);
    </script>
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